Federal prosecutors have charged Paul Ciancia, the suspect in the shooting rampage at Los Angeles International Airport, with murder and another charge, both of which could carry the death penalty, officials said this evening.

Ciancia, 23, on Friday shot a Transportation Security Administration officer, Gerardo I. Hernandez, at point-blank range, left the scene and then returned to shoot him again after Hernandez was seen moving on a surveillance video, the officials said. Hernandez later died. Ciancia also is accused of shooting two other TSA employees and a civilian, and causing other injuries.

Ciancia wrote in a signed note he carried with him to the airport that he targeted TSA officials and "made the conscious decision to try to kill" because he wanted to "instill fear in your traitorous minds," according to a federal affidavit outlining the charges against him.

"He targeted, specifically, TSA officers," FBI Special Agent in Charge David L. Bowdich told reporters this evening. "His intent was very very clear in his note."

Ciancia was charged today with murder of a federal officer and commission of violence at an international airport, both potentially punishable by life in prison or the death penalty.

In addition to the note and eyewitness accounts, investigators have surveillance video of the shootings, Bowdich said, and they are seeking additional digital media evidence potentially gathered by civilians at the airport. Such evidence or information can be submitted at https://laxshootingtips.fbi.gov.

However, investigators have not been able to speak directly with Ciancia because of wounds he suffered as he was subdued.

"He is receiving medical treatment," Bowdich said. "I'm not going to talk about his gunshot wounds. At the moment, he is unresponsive and we are unable to talk to him, as of today."

Bowdich credited a swift law enforcement response for preventing further carnage.

"They did stop this before, we believe, it would have been a much more grave action to include additional casualties," Bowdich said.

According to the affidavit, "at approximately 9:20 a.m. [PT Friday], Ciancia entered Terminal 3 at LAX and approached the Transportation Security Administration checkpoint. Ciancia pulled a Smith & Wesson .223 caliber M&P-15 assault rifle out of his bag and fired multiple rounds at point-blank range at a TSA officer [Hernandez] who was then on duty and in uniform, wounding the officer. Ciancia began to walk up an escalator, looked back at the wounded officer, who in video appeared to move, and returned to shoot the wounded officer again. The TSA officer was fatally wounded.

"Ciancia then fired his weapon on at least two other uniformed, on-duty TSA employees and one civilian passenger, all of whom sustained gunshot wounds," the affidavit added. "Ciancia was pursued and shot by a sergeant and an officer of the Los Angeles Airport Police."

Besides those shot, two civilians suffered what Bowdich described as "evasion injuries" caused by efforts to escape once the shooting erupted.

The shooting sent hundreds of passengers streaming out of the terminal, with many fleeing onto the airport runway. Dozens of flights to and from the airport were delayed or cancelled as a "tactical alert" was triggered for the Los Angeles Police Department.

Witnesses described a chaotic scene, as many ducked for cover inside bathroom stalls or dropped to the floor upon officers' commands.